In the complex society we are living in today, there are numerous occasions where individuals have to authenticate themselves by means other than personal recognition. Until recently, a common approach to this has been the issuance of personal identification cards which range in complexity depending on the purpose for which they are to be used. For situations that are deemed only of secondary importance, the cards may merely contain the individual's name, signature and an identification number. Here, the presentation of the card will be proof enough of the user's identity if the card signature matches that of the user's as taken at the time of use. For situations that require a more positive identification, such cards are also provided with the individual's photograph, as in the case of driver's licenses and passports.
Unfortunately, these identification instruments have commonly become the victims of illegal falsification and duplication. The rampant credit card fraud of recent years has certainly accentuated the inadequacy of using such personal instruments to authenticate oneself in many instances. To this end when bank-issued ATM cards were finally accepted and used by the American public in large numbers in the middle 1980's, a new identification means was introduced via what is now called the PIN number or Personal Identification Number which takes the form of an easily-memorisable 4-digit decimal number.
Even though there exist superior ways and methods for use in identifying or authenticating an individual, particularly those that use a person's natural body codes such as fingerprints, retina patterns and vocal audiograms or waveforms, they have to date only been deployed in highly special circumstances where the absolute security of one's identity warrants the additional complexity. Indeed the use of fingerprints to identify unique individuals has been around for well over a hundred years. Either “rolled” fingerprint or “flatly placed” fingerprint inked impressions are commonly used and the identification can be classified as “passive” because the individual is not required to perform any finger motions during the subsequent process of identification. As is well known, in collecting the so-called “rolled” fingerprint impressions, an individual's inked thumb or other fingers is rotated from one side to the other so that the entire pattern area can be printed on paper. Characteristic features or patterns of fingerprints such as “arches”, “loops” and “whorls” (referred to as “keys”) are routinely employed by fingerprint-identifying technicians to define fingerprint patterns for easier comparison and identification of them. The so-called Henry classification system is often used to determine if two prints are the same even though this system requires a skilled expert to compare the individual characteristics of the prints.
The classical approach of using fingerprints to identify individuals, albeit among one of the best known to date, is nevertheless rather complex and may require elaborate optical instruments such as high-power microscopes for detailed fingerprint pattern examinations. Collection of inked fingerprint impressions can be rather messy and also takes operator skill and a finite amount of time in order to do an adequate job. As briefly stated above, identification of fingerprints belonging to unique individuals using comparison methods requires trained expert or experienced technicians. Furthermore identification of individuals via fingerprint matching is not really an exact science and is by no means 100% objective or accurate. Added to all these is the fact that an individual's fingerprints are not even safe or fully protected from fraudulent use because most people frequently and inadvertently leave behind fingerprints while performing their daily routines. These fingerprints can be willfully recovered for illegal use as falsified personal identifications.
Not surprisingly, not all people feel comfortable in submitting their fingerprints for their personal identification such as credit cards, employee entrance cards in workplaces etc. except for very serious matters such as an extreme security check for sensitive federal appointments or for crime solving. One important reason behind this is the fact that there is an undesirable stigma of “criminal nature” associated with the use of fingerprints as a method of identification. Replacing specially trained and experienced fingerprint-identifying technicians requires the use of very complicated detection machines equipped with a complex processing algorithm. These equipments are therefore necessarily expensive. Still, in an effort to try to thwart the rampant credit card fraud, proposals have been advanced over the past several years to utilize one's fingerprint as a more secure way of authenticating credit card holders. The use of fingerprints along with the use of the so-called “smart cards”, namely cards that encapsulate a secure smart integrated circuit (IC) chip in the plastic in lieu of the fraud-prone magnetic stripe for storing sensitive and personal financial data, would surely eliminate once and for all the credit card fraud problem existing today. The development of the so-called biometric smart card using fingerprint template identification has been on-going for a number of years but unfortunately is still far from being a reality because of the credit card size and cost constraints of this method in addition to having to overcome very difficult technical challenges.
However, the technical obstacles that have been encountered to date in the implementation of the full-blown fingerprint identification approach in the biometric smart card should not be the determining factor in deciding whether or not this venerable identification method should be deployed in the future. Furthermore, the deployment of the retina pattern and the vocal audiogram or waveform as better and alternate ways to identify individuals will likely encounter the same constraint problems in size, cost and technical challenges without the benefit of a head start like the use of fingerprints. Today the rampant credit card fraud problem has not gone away. As a matter of fact, the problem grows worse and more serious every day that passes. Thus there presently exist ample reasons why a new and better methodology is needed in order to exploit the use of fingerprints as a secure way of authenticating individuals, especially in circumstances of primary importance like access to restricted area or restricted information, or authorization of credit cards, without the existing encumbrances of using fingerprints for identification as discussed above.
Ample prior art can be found in fingerprint detection apparatus and methods of using fingerprints for personal authentication and identification. Most of the prior art, with the exception of a few, deals only with two-dimensional fingerprint images, their acquisition methodology and apparatus, and their classification, interpretation and comparison as summarized below.
In U.S. Pat. No. 3,584,958 issued to Miller et al. in 1968, an identification system for identifying an individual using only a pre-defined and coded partial fingerprint, and not its entire 2-dimensional image, as a basis for comparison was advanced. The known information about the individual is contained as a coded partial fingerprint record in the form of an identification card issued to the individual. Similarly coded partial fingerprint record is generated for the individual at the time of identification by a complicated electro-optical-mechanical machine. The newly generated record is compared with the stored one looking for sufficient matching between them using an optical/photographic contrasting technique in order to establish authenticity. Although this invention teaches the use of only a partial fingerprint of an individual as a basis of comparison and thus simplifies somewhat the traditional approach of employing the entire 2-dimensional image of the fingerprint, the apparatus advanced is extremely complicated and the time required to make an identification easily takes more than a minute, and the individual has no personal choice in which portion of the fingerprint forms the basis of comparison for authentication.
In U.S. Pat. No. 4,003,656 issued to Leventhal in 1977, a method and apparatus for rapidly scanning the finger of an individual with a monochromatic beam of light and for producing an output in accordance with the light reflected by the finger which corresponds to the fingerprint of the finger was advanced. This teaching deals with the expeditious procurement of 2-dimensional fingerprint image for comparison with a stored reference. This method is classified as “passive” and the individual to be authenticated has no personal choice in the use of his fingerprint data (partial or complete) during the authentication process.
In U.S. Pat. No. 4,582,985 issued to Lofberg in 1986, the inventor advanced an identification system in the form of a credit card-shaped data carrier which contains a microprocessor capable of a priori storing and comparing supplied personal data of the individual at the time of authentication in order to enunciate a true or false decision. The sensor device comprises an array of micro-sensors arranged in the shape of a sensing matrix. The sensing elements can be thermo-resistive (a thermister having a temperature-dependent resistance) or thermo-electrical (thermocouple). The function of this sensing matrix is to determine the topographic contour (ridges and valleys) of a fingertip in intimate contact with it via differential temperature sensing, thereby obtaining a corresponding fingerprint line information. This invention deals only in 2-dimensional fingerprint images converted into digital data format for comparison with similar a priori stored fingerprint data of the individual to be identified.
In U.S. Pat. No. 4,607,384 issued to Brooks in 1986 an arrangement for generating a classification code for a fingerprint was advanced. For a fingerprint having a pattern of ridges and a plurality of reference features, a pair of cross-hairs is overlaid at a first one of the reference features. A line is then overlaid from a second one of the reference features to the first reference feature. The cross-hairs are oriented so that the line bisects a quadrant of the cross-hairs. The ridges crossed by predetermined portions of the cross-hairs are counted to generate the classification code. The overall objective of this invention is to provide an improved fingerprint classification arrangement in which fewer fingerprints are likely to have the same descriptor codes and deals with only 2-dimensional fingerprint images.
U.S. Pat. No. 4,784,484 issued to Jensen et al. in 1988 discloses an apparatus for the automatic scanning of a fingerprint comprising a scanning surface with a measuring means for the rate of movement of the finger in relation to the scanning surface. The apparatus further comprises a scanning area, a lighting means, an optical system and an electrical/optical scanning means giving an electrical signal as a function of the fingerprint when the finger is moved in contact with the scanning surface in a predetermined direction. The scanning is undertaken along a scanning line which is imaged onto a linear array of point-sized photodiodes coupled electrically to both a control and an output circuit for generating a line image of the fingerprint for the moving finger. The subsequent digital measurements can be stored in a dedicated memory which holds up to 256 lines of 256x1 digitized linear photodiode outputs equivalent to a complete fingerprint scan.
Additional teachings of fingerprint identification systems and methods of related interest may be found in other U.S. patents, including—U.S. Pat. No. 6,097,035 issued to Belongie et al. in 2000; U.S. Pat. No. 6,241,288 B1 issued to Bergenek et al. in 2001; U.S. Pat. No. 6,259,108 B1 issued to Antonelli in 2001; and Pub. 2001/0026636 A1 issued to Mainguet in 2001.
There is little doubt that the prior inventions summarized above have made significant progress towards simplifying the overall mechanics for the acquisition, classification and comparison of fingerprints. They have also removed in some cases the subjectivity and ambiguity in the employment of the well-known Henry classification system to determine if two prints are the same. However, as will be described in more detail below, the prior art of fingerprint detection/comparison apparatus and methods, including the use of automatic scanning of fingerprints, partial fingerprint images, fingerprint-reading systems and new classification arrangements, still fail to achieve the needed and valued objectives of overall simplicity, unusually high security, low cost and other new capabilities required for this identification technique to be fully functional, expeditious and more importantly, readily accepted by the general public for much wider application and usage in the future.